To Inspect or Not to Inspect: Which Pipeline is First?

Palm Beach County Water Utility Department (WUD) owns and operates a wastewater collection system consisting of 1,250 miles of gravity sewer pipe ranging in size from 4” to 30” in diameter, and 600 miles of wastewater force main that have been in operation for over 50 years. PBCUD developed an engineering-based methodology to effectively implement a long-term capital improvement program (CIP), to restore pipeline service life and forecast financial needs for its wastewater assets using a risk-based approach to ranking the pipeline segments for evaluation using the latest inspection methods. The process involved a unique pump runtime analysis was performed on the gravity sewer system to statistically correlate excessive lift station pumping periods to recorded historic high rainfall events and high groundwater periods (inflow and infiltration (I/I)), to identify the worst areas indicative of cracked or leaking sewers and has resulted in a multi-year program to continue inspection efforts.